1. Field of the Invention
The present invention relates to an information signal processing apparatus, a picture information converting apparatus, and a picture displaying apparatus.
2. Description of the Related Art
When an output picture signal is generated with an input picture signal in such a manner that the scanning line structure of the output picture signal is different from the scanning line structure of the input picture signal, a dedicated circuit for the output picture signal may be used. When a sum-of-product calculation is performed, a plurality of calculated results may be required. To obtain a plurality of calculated results, respective calculating circuits may be switched over. However, when the circuits are switched over, since the hardware scale may become large and the circuits may become redundant.
As a practical application, when an SD signal is converted into an output signal with high quality and high resolution, circuits corresponding to the types of output signals are disposed. A relevant circuit is used corresponding to a designated output signal. In this method, the hardware scale becomes large and circuits become redundant. To obtain an output picture signal corresponding to a picture pattern of an input picture signal, a plurality of output signals are required. It is considered that an interlace SD (standard definition) picture signal having 525 scanning lines is converted into an interlace HD (high definition) picture signal having 1050 scanning lines. Since the number of scanning lines is doubled, in the case of a natural picture, an output picture signal with high quality and high resolution is obtained. However, since the output picture signal is an interlace picture signal, in the case of a graphic picture, a line flicker becomes conspicuous. Thus, corresponding to the type of an input picture signal, the scanning line structure of an output picture signal should be switched over.
As a known method for removing a line flicker component, an interlace signal is converted into a progressive signal. However, in this method, an input signal is linear-interpolated and an interpolated signal is obtained. Thus, the resolution of the output signal cannot be improved against that of the input signal. In addition, when an interpolating method (for a still picture process or a moving picture process) is switched over corresponding to the detected result of a motion, the difference of resolution between the original signal and the interpolated signal becomes large. In particular, when a motion is incorrectly detected, the picture quality largely deteriorates.
As related inventions of the present invention, the applicant of the present invention has obtained the following US patents.
1. U.S. Pat. No. 5,379,072: Digital Video Signal Resolution Converting Apparatus
2. U.S. Pat. No. 5,666,164: Image Signal Converting Apparatus
An object of the present invention is to prevent a hardware scale from increasing against a plurality of circuit blocks being switched over. In other words, an object of the present invention is to provide an information signal processing apparatus that allows the operation state of a signal processing circuit thereof to be varied corresponding to an external operation condition setup signal. Another object of the present invention is to provide a picture information converting apparatus and a picture displaying apparatus that allow an output picture signal with a designated scanning line structure to be obtained.
A first aspect of the present invention is an information signal processing apparatus, comprising a signal processing circuit for performing a predetermined process for an input information signal, a control signal source, disposed outside the signal processing circuit, for supplying a control signal to the signal processing circuit, an operation condition setting circuit for generating an operation condition setup signal for the signal processing circuit corresponding to the control signal, and a signal varying circuit for varying an operation state of the signal processing circuit corresponding to the control signal.
The signal processing circuit may have at least two processing portions, the signal processing portion causing the operation state of at least one (referred to as designated processing portion) of the processing portions to vary corresponding to the operation condition setup signal, the operation state of the other process portion being varied corresponding to the variation of the operation state of the designated process portion.
A second aspect of the present invention is a picture information converting apparatus for generating a plurality of output picture signals having different scanning line structures with an input picture signal, the apparatus comprising a first data selecting means for selecting a plurality of second pixels of the input picture signal present in the vicinity of a first pixel generated as an output picture signal, a second data selecting means for selecting a plurality of third pixels of the input picture signal present in the vicinity of the first pixel generated as the output picture signal, a memory means for storing a pre-obtained estimation expression coefficient, a pixel value generating means for generating the first pixel with the second pixels selected by the first data selecting means and a linear estimation expression of the estimation expression coefficient, a class determining means for generating class information corresponding to the third pixels selected by the second data selecting means and supplying the estimation expression coefficient to the pixel value generating means corresponding to the class information, a scanning line structure converting means, connected to the pixel value generating means, for converting a conversion picture to a designated scanning line structure, and a controlling means for receiving a control signal that designates a scanning line structure of the output picture signal and switching over the second pixels and the third pixels selected by the estimation expression coefficient, the first data selecting means, and the second data selecting means corresponding to the control signal.
A third aspect of the present invention is a picture displaying apparatus for receiving an input picture signal and displaying the input picture signal to a displaying unit, the apparatus comprising a picture information converting unit, disposed between an input picture signal source and the display unit, for generating a plurality of output picture signals having different scanning line structures with the input picture signal, wherein the picture information converting unit comprises a first tap selecting means for selecting a plurality of second pixels of the input picture signal present in the vicinity of a first pixel generated as an output picture signal, a second tap selecting means for selecting a plurality of third pixels of the input picture signal present in the vicinity of the first pixel generated as the output picture signal, a memory means for storing a pre-obtained estimation expression coefficient, a pixel value generating means for generating the first pixel with the second pixels selected by the first tap selecting means and a linear estimation expression of the estimation expression coefficient, a class determining means for generating class information corresponding to the third pixels selected by the second tap selecting means and supplying the estimation expression coefficient corresponding to the class information to the pixel value generating means, a scanning line structure converting means, connected to the pixel value generating means, for converting a conversion picture to a designated scanning line structure, and a controlling means for receiving a control signal that designates a conversion method and switching over the second pixels and third pixels selected by the estimation expression coefficient, the first tap selecting means, and the second tap selecting means corresponding to the control signal.
According to the present invention, since one signal processing circuit that accomplishes a plurality of signal processing functions corresponding to an operation condition setup signal, the hardware scale can be reduced in comparison with a structure of which a plurality of circuits are switched. In the picture information converting apparatus according to the present invention, an input picture signal can be converted into a designated one of a plurality of output picture signals having different scanning line structures. Thus, an input picture signal can be converted into an output picture corresponding to a picture pattern of the input picture signal. In this case, the hardware scale can be prevented from becoming large. In addition, according to the present invention, since pixel values are generated with an estimation prediction expression that is optimum in each class. Thus, a still picture and a moving picture can be output with high picture quality.
The above, and other, objects, features and advantage of the present invention will become readily apparent from the following detailed description thereof which is to be read in connection with the accompanying drawings.